My latest return is a skirt from Old Navy:
I added a zipper to the underskirt:
Which unzips to reveal a little tuft of aberrant decoration: a crease of tulle, sequins and crystal:
Those views show the garment with the outer layer flipped up to reveal the underskirt. Here's the garment turned inside out, from which vantage the alteration is visible, but not terribly noticeable:
I was feeling nervous about this one, so I cashed in a favor to have someone else return it for me, but all went quite smoothly.